Process and apparatus for burning gas for heating purposes



, M. W. PITNER. I PROCESS AND APPARATUS FOR BURNING GAS FOR HEATING PURPOSES.

APPLICATION FILED FEB. 7, I914- Patented Apr. 27, 1920.

2 SHEETS-SHEET I.

M. W. PITNER.

PROCESS AND APPARATUS FOR BURNING GAS FOR HEATING PURPOSES.

APPLICATION FILE FEB. 7, 1914.

1,338,327, I Patented Apr. 27, 1920.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

MARION W. PI'INER, OF CHICAGO,.ILLINOIS, ASSIGNOR T0 PI'I'NER GAS APPLIANCE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

Specification of Letters Patent.

' Patented. Apr. 27, 1920.

Application filed February 7, 1914. Serial No. 817,187.

To all whom it may concern: 7

Be it known that I, MARION W. PITNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented-certain new and useful Improvements in Processes and Apparatus for Burning Gas for HeatingPurposes, of which the following is a specification.

My invention relates, in general, to a process of heating with gaseous fuel and also to apparatus for making use of the process.

My invention relates more particularly to a process of heating whereby a device or tool is heated by burning a mixture of combustible gas and air, and the heat transferred by said devic'e or tool to the material to be heated, as in laundry irons, water heaters, cooking utensils, andthe like.

My invention is particularly useful where the material is to be heated at temperatures below the kindling temperature of the gaseous mixture being used.

In burning gas for heating purposes, it is customary to mix air with the gas before it is inflamed in order to more fully utilize the heat generating capacity of the gas. Difficulties are encountered when it is attempted to mix with the gas a suflicient quantity of air to secure the maximum heat from the combustion thereof, inasmuch as the mixture with the gas of more than a predetermined limited quantity of air results in an explosive mixture, which produces such intense heat that flashing bac occurs, that is, the mixture between the flame and the point where the gas is mingled with the air is heated to the ignition point so that the flame propagates backto the gas, which then burns at its point of discharge before being mixed with the air." The greater the velocity of the mixture of air and gas the lower will be the relative'rate of propagation, and hence the greater'the velocity the greater can be the proportion of air without'danger of flashing back, but as the velocity is limited by the pressure of the gas supply the proportion of air which may be mixed with the gas is correspondingly limited. I p

In the practice of my invention by quickly dissipating the heat from the combustion point of amixture of air and gas, the mixture back of the point of combustion will not be heated to the kindling point, and hence flashing back or back firing will not occur, even when a much' greater proportion of air is mixed with the gas than has heretofore been practical.

The primary object of my invention is to provide a process of burning a mixture of air and combustible gas for heating purposes, by the practice of which a much larger proportion of air may be mixed with the gas than has heretofore been practicable, and the practiceof which will therefore result in greater utilization of the heat generating capacity of the gas than has heretofore been attained.

A further object of my invention is to pro vide an apparatus for the practice of my new process in which a mass of metal, or other material of high heat conductivity, will be'economically heated for various useful purposes, such, for instance, as ironing.

A still further object of my invention is to provide an improved gas heated sad iron which will be heated to the desired degree with a minimum consumption of gas.

My invention will be more fully disclosed hereinafter with reference to the accompanying drawings, in which the same is illustrated as embodied in convenient and practical form, and in which Figure 1 is a'perspective view of a sad iron so constructed as to utilize my new process.

Fig. 2 is a plan view of the body portion of the iron, the cover having been removed therefrom.

Fig. 3 is a sectional view taken on the line 3-3 ofFig. 1.

Fig. 4 is a sectional view taken on the line 4-4 of Fig. 1.

Fig. 5 is a plan view, parts being broken awa Fig. isan enlarged side elevational view of a portion of the sad iron shown in Fig. 1,

parts being broken away.

Fig. 7 is a crosssectionalview taken on line 7-7 of Fig. 3; and

Fig. 8 is a perspective view of the .bolt which connects the cover to the body portion.

Similar reference characters are used to designate similar parts in the several figures of the drawings. i

Reference letter A designates the body portion of a sad iron made, as is usual, of

preferably cast, and in the casting there is formed in the top thereof a chamber B surrounded by a flange 6. At each side of this chamber is formed a plurality of recesses Z), 5 b 6* and 5 In a plane below the chamber B there is formed a chamber C comprising parallel channels G, C and G extending longitudinally, and a series of transverse channels cl, (Z (Z (Z (Z and d which intersect the longitudinal channels. The intersection of the longitudinal and transverse channels form two longitudinal series of spaced posts A and A The outer walls of the longitudinal channels C and C are provided with recesses c, 0 0 0* and 0 which communicate with the adjacent channels. The central longitudinal channel C extends to a lower plane than the side longitudinal channels, and communicates with a series of transverse channels 6, e 0 e and e which extend to the outer surfaces of the body portion A of the iron in staggered relation to the transverse channels d to (Z inclusive.

The diaphragm F, which separates the chamber B from the underlying longitudinal and transverse channels, is provided with a series of longitudinal and transverse intersecting passages, the longitudinal passages being designated F, F and F and the transverse passages f to 7, respectively. These passages may be conveniently formed by a rotary saw after the body portion A has been cast. The longitudinal passages connect the chamber B' with the underlying longitudinal channels C, C and C respectively. while the transverse passages connect the chamber B with the underlying transverse passages c" to 0", respectively.

G designates a cover having a shallow recess in its under surface and provided with a peripheral flange 9 adapted to substantially register with and overlie the flange 6 around the chamber B in the body portion of the iron. Supported by the cover Gr within the flange 9 is a sheet of asbestos packing H, which overlies at its outer edge the flange 6 and also the inwardly projecting metal portions which form the recesses b to :5 respectively.

K designates a bolt having screw-threaded fends,:thelower of which engages 'within a screw-threaded opening in the diaphragm F, while the upper projects through a hole in theasbestos packing H and cover G. L designates a curved metal strip which: is provided with spaced ends, between which is secured a handle L in any suitable manner, as by means of screws Z and Z Thelower portion of the strip L is provided with a hole, through which the-threadedend of the bolt extends. A nut kengages the upper screw-threaded end of the bolt, and thereby secures the strip L with the handle L to the body portionvA of the iron, and coincidently tightly clamps the cover G to the body portion of the iron. When thecover is :thus clamped to the top of the body portion, the asbestos packing is forced into close engagement with the flange 6, thereby forming an air-tight joint between the peripheries of the cover and engaged body portion of the iron.

In order to provide a heat insulation for the handle L, a strip of asbestos It is interposed between the upper surface of the cover G and the supporting member L of the handle, as clearly shown inFig. 6. A recess 9 is preferably formed in the upper surface of the cover to receive the strip of asbestos h.

The cover G is provided with an interiorly screw-threaded opening G leading to the. under surface of the cover, and hence communicating with the chamber B. M designates a mixing chamber for air and gas,which is preferably in the form of a tube having a lower screw-threaded end M in engagement with the screw-threaded opening G through the cover. m designates the passages through which air'passes into the mixing chamber, while N designates a supply conduit which communicates with the mixing chamber and is secured thereto by a suitable coupling ring m. 0

designates a discharge nipple for reducing the flow of gas from the conduit N into the mixing chamber M.

The operation of the specific device shown in the drawings and above described for the practice of my improved process is as follows:

The conduit N may be of any desired length, and is connected with a source of gas supply, such, for instance, as a burner for illuminating gas. The gas flows through the conduit N, into the mixing chamber M, where air passes through the openings on and is mixed with the gas. The mixture then flows through the coupling G 'to'the distributing chamber B, and thence passes, through the narrow slits in the flame-intercepting diaphragm F, into the'combustion chamber C, where the mixtureis ignited. and burns adjacent the lower ends'of the slits in the diaphragm. The products of combustion pass from the longitudinal channels C, C ,and C and also from the-intersecting transverse channels 0, .0 0 0*, and 0 into the transverse channels d to 03*, respectively,-whichi extend to the exterior of the body portion of the iron. When the body portion of the iron is provided with other exhaust passages, such as those designated in the drawings 6' to e the products of combustion also pass downwardly through the central channels G into the lower discharge channels.

In my new process, I pass the mixture through a flame-intercepting diaphragm at a much lower velocity than the rate at which a flame would propagate through the mixture, so that the flame burns relatively slowly for a mixture of this kind, and burns very close to the metal forming the flameintercepting diaphragm, thus making it possible for it to absorb the heat at this very point, for it is a well-known fact that the ratio at which a body will absorb heat from another body increases as the diflerence in the temperature of the body absorbing the heat and the body supplying it increases.

In my new process, I can utilize the principles of the well-known Bunsen burner with gas at exceedingly low pressures, and supply all the air necessary for complete combustion, because the velocity at which I pass the mixture through the diaphragm is relatively low, while the area of a cross-section of the slots through diaphragm is relatively large, and the thickness of the diaphragm is relatively great, consequently preventing the gas from flashing back by keeping the temperature of the mixture, as it flows into and partly through the diaphragm, below its kindling ignition point, by providing ample absorbing material and heat conducting capacity in the diaphragm to conduct the heat away and deliver it to the material to be heated at a suflicient rate to maintain the temperature of the mixture, at some point in the diaphragm, below its kindling point.

The passages through the flame-intercept ing diaphragm are so restricted in width and extend through such a mass of the metal of the iron that the heat of the combustion of the mixture is distributed throughout a mass of the metal, so that the heat generated by the combustion of the mixture is quickly dissipated, owing to the high heat conductivity of the mass of metal of which the iron is formed which communicates the heat to the material to be heated. This rapid dissipation of the heat generated by the combustion of the mixture avoids the heating of the mixture passing through the intercepting diaphragm to its ignition point, and hence prevents flashing back. It

is therefore possible by the practice of my process to burn highly combustible mixture, inasmuch as the velocity of the mixture passing to the point of combustion is not relied upon to prevent flashing back, but flashing back is prevented by so rapidly conducting the heat away from the flame that the gas in the passageways leading to the point of combustion is not heated to its kindling point.

The slots, of course, must be thin enough to prevent flash-backs but below this point the thickness with the quantity and distributlon of the heat desired.

The quantity of air that will be drawn into a device ofthis kind depends upon the pressure on the gas, the construction of the air mixer, the amount of resistance caused by the flame-intercepting diaphragm, as well as any other parts of the air mixer, distributing chamber, and even the resistance offered to the escapement of the products of combustion. The resistance that is offered by the diaphragm is, in effect, greater when the device is hot than when it is cold, because the mixture passing through it is increased in volume by being increased in temperature. Furthermore, the character of the ingredients of the fuel gas obtainable throughout the world varies very considerably and to such an extent that the quantity of air necessary to supply suflicient oxygen for the complete combustion of the gas varies greatly, which is a condition that must be taken into consideration when constructing a burner to utilize my process.

I am aware cient oxygen mixed with it for its complete combustion, has been used heretofore; but it has usually been done, either by placing the gas under such a high pressure that it would draw sufiicient oxygen in through the air mixer and move the whole mixture at a higher velocity than the rate of propagation of a flame through such a mixture, thereby keeping the flame away from the orifice through which the gas is supplied; or else it has been done by supplyin both the gas and the oxygen by mechanica means and in such a way that the velocity of the mixture is likewise greater thanthe rate at which a flame would propagate through such' a mixture; and, while these mixtures may have been passed through a flame-intercepting diaphragm, the high velocity was necessary to prevent the gas from flashing back to'the orifice.

While I have illustrated a sad iron of certain-construction as the device for use in practising my improved process, yet I wish it understood that my process may be prac tised in various devices of other construction and for other purposes. The practice of my invention in its broadest aspect merely requires that the heat of the flame should be dissipated by the combustion device conducting the heat to the material to be heated so rapidly that the gaseous mixture back of the combustion point is not heated to its ignition point. While I have may vary in accordance that gaseous fuel, with suflimentioned air in the specification and in the annexed claims as being mixed with the combustible gas, yet it will be understood that other gases containing oxygen, or even oxygen itself, may in lieu of air be mixed with the combustible gas.

I claim:

1. A gas heated device formed of a relatively large mass of material of high heat conductivity having a surface adapted to contact with the material to be heated and comprising a distributing chamber and a combustion chamber, means for supplying a mixture of air and combustible gas to said distributing chamber, a flame intercepting diaphragm in direct heat conducting relation with said surface and separating said distributing chamber from said combustion chamber, said diaphragm having therethrough extended passages of restricted cross section connecting said chambers, and separated exhaust passages leading from said combustion chamber to the exterior of said device located intermediate of the combustion chamber and said surface.

2. Ina gas heated flat iron, the combination. with a body portion having a surface adapted to engage the articles to be ironed and comprising a distributing chamber and a combustion chamber, of a cover, an asbestos packing interposed between said cover and body portion, means for tightly clamping said cover to said body portion so as to form an air tight joint through the medium of said packing, a flame intercepting diaphragm formed integrally with said body portion and interposed between said distributing chamber and said combustion chamber, meansv for supplying a gaseous mixture to said distributing chamber, said diaphragm having restricted passages extending. therethrough and connecting said chambers, and said body portion having a plurality of series of passages leading from said combustion chamber to the exterior of the iron intermediate of the combustion chamber and said surface.

3. A gas heated sad iron comprising a body having a combustion chamber, a superposed gas distributing chamber, a relatively thick diaphragm separating said chambers and having restricted slots therein, a series of discharge ports from said combustion chamber, and a second series oflateral discharge ports leading from the combustion chamber below the first series and staggered relatively thereto.

4. A gas heated sad iron comprising a body having a combustion chamber, a superposed gas distributing chamber, a relatively thick diaphragm separating said chambers and having restricted longitudinal and transverse slots therein, a series of lateral discharge ports from said combustion chamber, and a second series of lateral discharge ports leading from the center of the combustion chamber below the first series and staggered relatively thereto.

In testimony whereof I have subscribed my name.

MARION l/V. PITNEB Witnesses:

Gno. L. WILKINSON, HENRY A. PARKS. 

